EP0227908A1 - Dispositif pour la mesure de tension en prenant des échantillons - Google Patents

Dispositif pour la mesure de tension en prenant des échantillons Download PDF

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Publication number
EP0227908A1
EP0227908A1 EP86114868A EP86114868A EP0227908A1 EP 0227908 A1 EP0227908 A1 EP 0227908A1 EP 86114868 A EP86114868 A EP 86114868A EP 86114868 A EP86114868 A EP 86114868A EP 0227908 A1 EP0227908 A1 EP 0227908A1
Authority
EP
European Patent Office
Prior art keywords
signal
input
output
amplifier
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86114868A
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German (de)
English (en)
Inventor
Dipl.-Ing. Balogh. András
Lajos Bella
Gyula Dipl.-Ing. Somogyi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MIKI MERESTECHNIKAI FEJLESZTO VALLALAT
Original Assignee
MIKI MERESTECHNIKAI FEJLESZTO VALLALAT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MIKI MERESTECHNIKAI FEJLESZTO VALLALAT filed Critical MIKI MERESTECHNIKAI FEJLESZTO VALLALAT
Publication of EP0227908A1 publication Critical patent/EP0227908A1/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R13/00—Arrangements for displaying electric variables or waveforms
    • G01R13/20—Cathode-ray oscilloscopes
    • G01R13/22—Circuits therefor
    • G01R13/34—Circuits for representing a single waveform by sampling, e.g. for very high frequencies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0046—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00
    • G01R19/0053—Noise discrimination; Analog sampling; Measuring transients

Definitions

  • the object of the invention is a device for voltage measurement by scanning, which can be used particularly in individual devices operating in the wide frequency range or in automatic measuring machines.
  • the selected mode of operation generally determines and limits the field of application of the measuring device.
  • the number of selectable systems is further narrowed when used in automatic measuring machines. With these measuring devices with an upper limit frequency of GHz order of magnitude, it is necessary to ensure fast functioning, great accuracy and good temporal and thermal stability.
  • the high-frequency signal to be measured arrives at the input of the detector circuit composed of diodes.
  • the DC voltage signal appearing at the output of the detector circuit is proportional to the true RMS value of the input signal at low input levels, but with the peak value of the input signal at large input levels due to the diode characteristics.
  • the transmission characteristic of the detector circuit is non-linear, furthermore the conversion takes place efficiency quickly decreases in the direction of the small levels.
  • the output signal of the detector circuit therefore arrives, after appropriate amplification, at the input of a non-linear amplifier.
  • the nonlinear amplifier compensates for the nonlinearity of the detector circuit with the aid of a breakpoint approximation circuit.
  • the output signal of the non-linear amplifier can be fed to a measuring device, or through an analog-digital converter to a digital display or for further processing of a computing machine.
  • the non-linear transmission characteristic of the detector has to be linearized with a non-linear circuit of refractive point approximation, but this requires a difficult adjustment depending on the individual diodes; - In the case of small and large input levels, the output signal of the detector circuit is proportional to the respective other parameter of the input signal (effective value, peak value), which is why the measurement of complex signals (e.g.
  • the function of the device operating on the principle of incoherent sampling is as follows.
  • the high-frequency signal to be measured arrives at the input of a scanner.
  • the scanner switches the signal to be measured, corresponding to the frequency of a voltage-controlled oscillator, for a very short time to the input of an amplifier of constant gain.
  • the sampling takes, for example, a few 100 psec long, so the input capacity of the amplifier is loaded in the entire frequency range of the Device to a voltage proportional to the instantaneous value of the signal to be measured recorded at the moment of the sampling, while it discharges between two samples.
  • the amplitude of the pulse series appearing at the output of the amplifier is therefore proportional to the instantaneous value of the signal to be measured at the time of a scan.
  • the frequency of the sampling changes stochastically in comparison with the signal to be measured, ie the sampling is incoherent, and sample values can be extracted from the signal to be measured in very large numbers
  • the statistical characteristic values of the sampled pulse series peak, middle and RMS value
  • the stochastic sampling takes place in such a way that the frequency of the voltage-controlled oscillator controlling the sampling is frequency-modulated by another oscillator.
  • the incoherent scanning principle has the following advantages over the detector type: -
  • the transmission characteristic of the scanner is linear, because the sampled switch is controlled by a signal of constant amplitude, in the following the conversion efficiency does not depend on the level of the signal to be measured; -
  • the output signal of the scanner has, regardless of the input levels, the statistical parameters of the signal to be measured, therefore the measurement can be clearly evaluated when measuring complex signals (eg noise); - Since the opening of the series switch of the scanner is carried out by a signal independent of the signal to be measured, the conversion efficiency of the scanner is independent of the level of the signal to be measured, so the device can be clearly zeroed.
  • the disadvantage of the device operating according to the principle of incoherent scanning is that the conversion efficiency of the scanner depends to a significant extent on the outside temperature, which appears to be an apparent gain change. This value is approximately three or four times the value which is characteristic of the devices working with diode detectors.
  • this problem is eliminated in such a way that an internal calibration unit is installed in the device, to the output of which the measuring input can be connected, and the device can thus be calibrated at the respective ambient temperature.
  • This calibration unit is actually an etalon, so it is quite expensive.
  • the disadvantage of this solution is also evident when it is used in an automatic measuring machine, since the duration of the measurement with the automatic measuring machine is significantly extended due to the temporary interruption of the measuring process.
  • the purpose of the invention in addition to maintaining the advantages of the device operating according to the principle of incoherent scanning, is to provide a solution which, despite the changes in the temperature-dependent parameters of the components and circuit units used, ensures a temperature-independent measurement without interrupting the measuring process.
  • the set goal is achieved according to the invention by using an auxiliary signal, the auxiliary signal ensuring the stable measurement without falsifying the measured voltage value.
  • the invention is therefore a device for voltage measurement by scanning, which has a unit that scans the voltage to be measured, an amplifier that amplifies the sampled signal and a signal processing unit that evaluates the amplified signal of the prescribed measurement task, the scanning unit being connected to a control generator.
  • the device has an auxiliary signal auxiliary oscillator, and between the scanning unit and the signal processing unit an amplifier of controllable amplification and a differential circuit, the auxiliary signal being connected, on the one hand, with the voltage to be measured, to a signal input of the scanning unit, and, on the other hand, to an input of the differential circuit by a phase shifter, furthermore, between the output of the differential circuit and / or its other input connected to the controllable amplifier on the one hand, and the control input of the controllable amplifier on the other hand, a feedback branch which is selective to the frequency of the auxiliary signal is connected.
  • the auxiliary signal between the scanning unit and the differential circuit is constantly superimposed on the voltage signal to be measured, but after the differential circuit it already has such a small value that it does not influence the voltage measurement.
  • the feedback branch which is connected upstream and / or downstream of the differential circuit and is selective to the frequency of the auxiliary signal, can sense the auxiliary signal, if necessary in addition to appropriate amplification, and, due to this, can reverse control by the controllable amplifier. If the feedback branch is connected upstream of the differential circuit, its gain can be much smaller because the auxiliary signal to be sensed is larger here.
  • the solution according to the invention does not require a highly stable auxiliary oscillator.
  • the feedback branch can advantageously be designed such that it connects to the output of the differential circuit and contains a further amplifier, a phase-sensitive rectifier controlled by the output signal of the phase shifter and a first low-pass filter, which are connected in series.
  • the selectivity of the feedback branch can be increased even further if the further amplifier has a low-pass characteristic, for example of the integrated type.
  • the feedback branch is connected to the other input of the differential circuit mentioned and contains a phase-sensitive rectifier, a DC voltage difference element, a further amplifier and a first low-pass filter, an input of the DC voltage difference element being connected to the phase shifter by means of a rectifier.
  • the auxiliary signal felt by the feedback branch is larger, so the signal-to-noise ratio is better.
  • the feedback branch is connected to the output and also to the other input of the differential circuit mentioned.
  • the feedback branch contains a first differential element, with its two inputs connected to the output and to the mentioned other input of the differential circuit, a second differential element, a further amplifier, a phase-sensitive rectifier and a first low-pass filter, which are connected in series, wherein an input of the second differential element and the control input of the phase-sensitive rectifier are connected to the phase shifter.
  • the mentioned other input of the differential circuit is connected to the output of the controllable amplifier by interposing a sampling and holding circuit which is controlled with a delay in relation to the sampling unit. It is expedient if, in addition to the regulation with the selected auxiliary signal, the output of the sampling and holding circuit is connected to a feedback input of the sampling unit by means of a second low-pass filter. This second negative feedback initially ensures the DC stability of the scanning unit.
  • the solution according to the invention is particularly suitable for measurements of stochastic character carried out with incoherent scanning.
  • the generator controlling the scanning unit is a voltage-controlled oscillator, the control input of which is connected to a voltage source from the variable output signal.
  • the invention can also be used in a measurement carried out with coherent or Shannen's scanning.
  • the generator controlling the scanning unit is a unit that generates a signal corresponding to the respective frequency of the voltage to be measured, or a signal of constant voltage.
  • the frequency of the auxiliary oscillator is less than the lower limit of the frequency range of the voltage to be measured. As a result, the measurement accuracy can be increased even further.
  • An embodiment designed for the purpose of high-frequency voltage measurement is particularly advantageous if the scanning unit contains an analog diode switching circuit, the signal input of which is connected on the one hand through a capacitor to the input which accepts the voltage to be measured, and on the other hand through resistors connected in series and a feedthrough capacitor to the output of the auxiliary oscillator is.
  • the signal processing unit should be selected according to the desired measuring task.
  • This can be a circuit measuring the effective value, the peak value or the electrolytic mean value, or a combination thereof with the possibility of switching.
  • the signal processing unit can be designed as an analog processing unit or a digital processing unit connected after an analog-digital converter.
  • the high-frequency signal to be measured arrives from the input 15 through a coupling unit 1 to the signal input 17 of a scanning unit 2.
  • an auxiliary signal of a correspondingly selected frequency is connected by the coupling unit 1 to the signal input 17 of the scanning unit 2 at the output 16 of an auxiliary oscillator 14.
  • the task of the coupling unit 1 is the adapted coupling of the voltage signal to be measured and the auxiliary signal to the signal input 17 of the scanning unit 2.
  • the scanning value at the output 20 of the scanning unit 2 is the sum of the instantaneous values of the signal to be measured and the value recorded at the moment of scanning Auxiliary signal proportional.
  • the opening of the scanning unit 2 is carried out by its control input 18 by a generator 12, in the embodiment shown by a voltage-controlled oscillator, the output frequency of the latter is modulated by a voltage source 11 with a variable output signal, for example from a sawtooth generator or sine wave oscillator.
  • the scanning unit 2 applies the signal coming to its signal input 17 to its output 20 and thereby to the input of an amplifier 3 of controllable amplification.
  • the storage capacitance arranged in the scanning unit 2 (see capacitor 43 in FIG. 4) is charged to a voltage which is proportional to a total value of the signal to be measured and the auxiliary signal which is recorded at the moment of scanning. This capacitance loses its charge between two scans, ie the capacitor 43 discharges.
  • the output signal of the amplifier 3 of controllable gain is connected to the input 22 of the sample and hold circuit 4.
  • the sampling and holding circuit 4 samples the signal produced by the sampling unit 2 and amplified by the amplifier 3, as a result of which it only carries out signal shaping (amplification), but does not influence the statistical characteristics of the sampled signal.
  • the sampling and holding circuit 4 is to be controlled synchronously with the sampling unit 2, namely in such a way that it is to sample the signal appearing at the output of the sampling unit 2 or accordingly at the output of the amplifier 3 at the maximum value. This requires a constant time delay.
  • the sampling and holding circuit 4 is controlled by its control input 23 from the correspondingly delayed output signal of the generator 12.
  • the output signal of the sample and hold circuit 4 arrives on the one hand through a low-pass filter 10, as a DC voltage feedback at the feedback input 19 of the scanner unit 2, and on the other hand connects to an input 24 of the differential circuit 5.
  • the signal of the auxiliary oscillator 14 is connected to the other input 25 of the differential circuit 5 by a phase shifter 13. As long as the auxiliary signal of the auxiliary oscillator 14 arrives from the input of the coupling unit 1 to the input 24 of the differential circuit 5, it undergoes a phase shift, the task of the phase shifter 13 is the in-phase nature of the signals of the frequency of the auxiliary oscillator arriving at the inputs 24 and 25 of the differential circuit 5 14 to secure.
  • the difference signal of frequency of Auxiliary oscillator 14 in comparison with the signal to be measured, practically negligible at the output of the differential circuit 5. If at the input 24 of the differential circuit 5 a signal of the auxiliary oscillator 14 of an amplitude that matches the amplitude of the signal of the auxiliary oscillator 14 connected to the input 25 cannot be found, the output of the differential circuit 5 is dependent on the direction of the deviation phase-correct (with the signal of the base oscillator matching or opposite phase) difference signal of the frequency of the auxiliary oscillator 14.
  • the output of the differential circuit 5 is closed by an amplifier 7 of low-pass characteristics, for. B. of the integrated type, to the input 26 of the phase-sensitive rectifier 8.
  • the output signal of the phase shifter 13 is connected to the control input 27 of the phase-sensitive rectifier 8.
  • the task of the amplifier 7 of the integrated type after integrating the sampled signal, is to amplify the differential signal of the frequency of the auxiliary oscillator 14.
  • the output of the phase-sensitive rectifier 8 is connected by a low-pass filter 9 to the control input 21 of the amplifier 3 of controllable gain.
  • the amplifier 7, the phase-sensitive rectifier 8 and the low-pass filter 9 form a feedback branch 28.
  • the phase-sensitive rectifier 8 uses a very high selectivity to produce a correct control DC voltage from the phase-corrected difference signal, which ultimately changes the amplification of the amplifier 3 to such an extent that at the inputs 24 and 25 of the differential circuit 5 signals of frequency of the auxiliary oscillator 14 should have the same amplitudes.
  • the difference signal of the frequency of the auxiliary oscillator 14 decreases at the output of the differential circuit 5, so, in the case of a correspondingly high gain, the signal of the frequency of the auxiliary oscillator 14 which can be measured at the output of the differential circuit 5, compared to the signal to be measured, always kept at a predetermined minimum level, so it does not cause an error in the measurement.
  • This configuration is advantageous because the difference circuit 5 can be used simultaneously as a difference-forming element of the feedback, and the difference circuit 5 is located in the control loop.
  • the feedback branch 28, deviating from FIG. 1 can also be designed such that it is connected between the input 24 of the differential circuit 5 and the control input 21.
  • a difference formation should also be carried out in the feedback branch 28 since the difference circuit 5 is not in the control circuit in this case.
  • a phase-sensitive rectifier 52 connects directly to the output of the sample and hold circuit 4, the filtered output of which arrives at an input of a DC voltage difference element 51, the other input of which is fed by the filtered signal of the rectifier 50 connected to the output of the phase shifter 13.
  • the output of the DC voltage difference element 51 is connected to the control input 21 by an amplifier 53 which adjusts the loop gain and by a low-pass filter 54 which is required for stability.
  • the auxiliary signal with a larger amplitude for the feedback can be obtained, in the following the signal-to-noise ratio is better.
  • the feedback branch 28, in deviation from FIG. 1, connects both to the output and to the input 24 of the differential circuit 5 through inputs of a differential element 60, at the output of which practically only that which is at the input 24 to measuring signal superimposed auxiliary signal appears.
  • the output of the differential element 60 arrives at an input of a differential element 61 which carries out the difference formation of the control circuit, the other input of which is connected to the output of the phase shifter 14.
  • the output signal of the differential element 61 arrives through an amplifier 62 at the phase-sensitive rectifier 63, which is also controlled by the output signal of the phase shifter 13.
  • the output signal of the phase-sensitive rectifier 63 controls the control input 21 through the low-pass filter 64 required for stability.
  • Such a control loop can be found in the device according to the invention, which, by ensuring a temperature-independent amplification for the auxiliary signal of the auxiliary oscillator 14, also automatically secures the same for the signal to be measured.
  • a signal processing unit 6 is also connected to the output of the differential circuit 5. Such a pulse series arrives in the signal processing unit 6, which carries only the statistical characteristic values of the signal to be measured and in which the effect of the signal on the frequency of the auxiliary oscillator 14 is negligible.
  • the signal processing unit 6 generates at its output 29 a signal proportional to its peak value, electrolytic mean and / or effective value from the sampled pulse series, and this signal is proportional to the corresponding value of the signal to be measured and calibrated according to the corresponding value of the signal to be measured .
  • the signal at the output 29 can be transmitted to an arithmetic machine for further processing by an analog-digital converter (not shown).
  • the signal processing unit 6 can be a more complicated, a statistical characteristic value (eg amplitudes distribution) or several characteristic values can also be a determining circuit, and can be constructed from both analog and digital circuits.
  • FIG. 4 shows such an embodiment of the coupling unit 1 and the scanning unit 2 according to FIG. 1, which is also suitable for the purpose of a millivolt meter operating in a wider frequency range.
  • the voltage signal to be measured arrives from the input 15 through a capacitor 30 to the signal input 17 of the scanning unit 2.
  • the sinusoidal or rectangular auxiliary signal at the output 16 of the auxiliary oscillator 14 of e.g. 1 kHz arrives at the input 17 through a resistor 33, a feedthrough capacitor 32 and a further resistor 31.
  • the coupling unit 1 thus adds the two signals and at the same time ensures with the feedthrough capacitor 32 that the high-frequency signal to be measured (e.g. 100 kHz - 1 GHz) cannot come to the output 16.
  • the input 17 connects through an analog diode switching circuit 34 to the input of an amplifier 47, while the output of the amplifier 47 forms the output 20 of the scanning unit 2.
  • the diode switching circuit 34 contains four bridged diodes 37, 38, 39 and 40, which are connected by resistors 35 and 36 between supply voltages -U T and + U T.
  • the points of the diode bridge circuit which follow the resistors 35 and 36 are fed by the secondary winding of a pulse transformer 48 with positive or negative pulses which are synchronized with one another, corresponding to those obtained on the primary winding by the control input 18 from the generator 12, for example in the range from 100 to 150 kHz variable control, which determines the lower limit frequency of the measuring range.
  • the peak value of the positive and negative pulses is greater than the supply voltage U T , accordingly the diode switching circuit 34 is open during the period when the instantaneous value of the pulses exceeds the supply voltage U T.
  • This time duration is about 0.1 - 0.3 ns at about 1 GHz upper limit frequency of the measuring range.
  • a capacitor 43 which stores the sampled signal, is connected between the output of the diode switching circuit 34 and the ground.
  • the feedback input 19 connects through a resistor 46, a feed-through capacitor 45 and a further resistor 44, which is connected to the output of the low-pass filter 10.
  • the sampled sum signal of the signal to be measured and the auxiliary signal, on the one hand, and the feedback signal, on the other add up, and a corresponding signal appears at the output of amplifier 47, which is the output 20 of sampling unit 2.
  • the device according to the invention with a corresponding unit for current-voltage conversion is also suitable for current measurement.
  • this unit is a resistor, but it can e.g. also contain a current transformer if an earth-independent measurement is required.
  • the device according to the invention can be designed not only for single-channel but also for two-channel measurement, e.g. one channel for measuring the voltage, the other for measuring the associated current, and there the signal processing unit 6 can generate a signal proportional to the value of the complex impedance.
  • the main advantage of the invention is that no special thermal stability is required for the amplitude of the output signal from the auxiliary oscillator 14.
  • the difference circuit 5 forms the difference between the signals coming from the same auxiliary oscillator 14, so that the change in the amplitude of the auxiliary oscillator 14 does not cause an error.
  • the thermal stability of the system is only influenced by a change in the parameters of the phase shifter 13 or by a significant change in the frequency of the auxiliary oscillator 14.
  • the heat stability of the Parameter values of the phase shifter 13 and also that of the frequency of the auxiliary oscillator 14 can be easily secured by appropriate selection of the type of passive R, L, C elements used.
  • Another advantage of the invention is that, in addition to the temperature-dependent changes in the gain, it is also able to compensate for the changes occurring as a result of the aging of the components.
  • the economic advantage of the solution is that a significant improvement in the specification is achieved with a low-frequency element set, the price of which is negligible in addition to the material price of the complete device, furthermore the installation of a calibration unit in the device or the use of a variable in function of the temperature , expensive correction amplifier in the signal processing unit 6 unnecessary.
  • the device according to the invention corresponds in every respect to the special demands made of programmable devices which can be used in the measuring machines and which measure analog parameters. When used as a single device in the laboratory, it has better technical specifications than the similar devices available in this category.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Current Or Voltage (AREA)
EP86114868A 1985-11-18 1986-10-27 Dispositif pour la mesure de tension en prenant des échantillons Withdrawn EP0227908A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HU854375A HU196513B (en) 1985-11-18 1985-11-18 Apparatus for measuring voltage by sampling
HU437585 1985-11-18

Publications (1)

Publication Number Publication Date
EP0227908A1 true EP0227908A1 (fr) 1987-07-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP86114868A Withdrawn EP0227908A1 (fr) 1985-11-18 1986-10-27 Dispositif pour la mesure de tension en prenant des échantillons

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US (1) US4785236A (fr)
EP (1) EP0227908A1 (fr)
JP (1) JPS62209369A (fr)
HU (1) HU196513B (fr)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3338159B2 (ja) * 1994-02-10 2002-10-28 三菱電機株式会社 振幅・位相検出装置
US6262670B1 (en) * 1998-04-10 2001-07-17 Kevin R. Ballou Source measure unit having secondary feedback for eliminating transients during range changing
US6118278A (en) * 1998-08-18 2000-09-12 Hewlett-Packard Company Short circuit detection in particular for a measuring bridge
SE513954C2 (sv) * 1999-04-01 2000-12-04 Abb Ab Förfarande och system för bearbetning av signaler från en givare driven med en växelströmsexcitationssignal
US6265998B1 (en) * 1999-11-30 2001-07-24 Agere Systems Guardian Corp. Sampling device having an intrinsic filter
US6433524B1 (en) 2001-03-15 2002-08-13 Rosemount Aerospace Inc. Resistive bridge interface circuit
SE0601249L (sv) * 2006-06-07 2007-12-08 Abb Ab Förfarande och anordning för demodulering av signaler
FR2910162B1 (fr) * 2006-12-18 2009-12-11 Schneider Electric Ind Sas Dispositif de couplage de signal de mesure a isolation electrique et appareil electrique comportant un tel dispositif
DE102008029477A1 (de) * 2008-06-20 2009-12-24 Vacuumschmelze Gmbh & Co. Kg Stromsensoranordnung zur Messung von Strömen in einem Primärleiter
DE102008029475A1 (de) * 2008-06-20 2009-12-24 Robert Bosch Gmbh Stromsensoranordnung zur Messung von Strömen in einem Primärleiter
CN102262180A (zh) * 2011-07-05 2011-11-30 珠海市科荟电器有限公司 无线二次压降测试装置
EP2626864A1 (fr) * 2012-02-08 2013-08-14 VEGA Grieshaber KG Dispositif et procédé de balayage d'un signal
CN102841244B (zh) * 2012-09-19 2014-10-15 华北电力大学（保定） 电网电压骤变的快速检测方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3412331A (en) * 1965-04-29 1968-11-19 Hewlett Packard Co Random sampling voltmeter
DE1293249B (de) * 1966-04-28 1969-04-24 Thomson Houston Comp Francaise Schaltungsanordnung zur Feststellung sinusfoermiger elektrischer Signale
DE1949056A1 (de) * 1969-09-29 1971-04-01 Funkwerk Erfurt Veb K Schaltungsanordnung zum Messen und zur Anzeige sehr kleiner hochfrequenter Spannungen
US3896389A (en) * 1972-04-12 1975-07-22 Comstron Corp Sensitive wide band voltmeters
GB2078980A (en) * 1980-06-14 1982-01-13 Marconi Instruments Ltd Sampling measurement circuits

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4313212A (en) * 1978-08-31 1982-01-26 Racal Communications Inc. Electrical circuit arrangements, for example for use with communications receivers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3412331A (en) * 1965-04-29 1968-11-19 Hewlett Packard Co Random sampling voltmeter
DE1293249B (de) * 1966-04-28 1969-04-24 Thomson Houston Comp Francaise Schaltungsanordnung zur Feststellung sinusfoermiger elektrischer Signale
DE1949056A1 (de) * 1969-09-29 1971-04-01 Funkwerk Erfurt Veb K Schaltungsanordnung zum Messen und zur Anzeige sehr kleiner hochfrequenter Spannungen
US3896389A (en) * 1972-04-12 1975-07-22 Comstron Corp Sensitive wide band voltmeters
GB2078980A (en) * 1980-06-14 1982-01-13 Marconi Instruments Ltd Sampling measurement circuits

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Publication number Publication date
HU196513B (en) 1988-11-28
JPS62209369A (ja) 1987-09-14
US4785236A (en) 1988-11-15
HUT41906A (en) 1987-05-28

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